FIG. 1 shows an example of a conventional fuel injection device, in which a flat intermediate element is provided on a fuel injection valve installed in a receiving bore of a cylinder head of an internal combustion engine. In a conventional manner, such intermediate elements are placed on a shoulder of the receiving bore of the cylinder head as supporting elements in the form of a washer. With the aid of such intermediate elements, manufacturing and assembly tolerances are compensated, and a mounting free of transverse forces is ensured even given a slightly oblique positioning of the fuel injection valve. The fuel injection valve is particularly suitable for use in fuel injection systems of mixture-compressing spark-ignited internal combustion engines.
Another type of simple intermediate element for a fuel injection device is described in German Patent Application No. DE 101 08 466 A1. The intermediate element is a support ring having a circular cross-section, situated in an area in which both the fuel injection valve and the wall of the receiving bore in the cylinder head run in the shape of a conical frustum, said ring acting as a compensating element for bearing and supporting the fuel injection valve.
Intermediate elements for fuel injection devices that are more complicated and significantly more expensive to produce are also described in, inter alia, German Patent Application Nos. DE 100 27 662 A1 and DE 100 38 763 A1, and European Patent No. EP 1 223 337 A1. These intermediate elements are distinguished in that they all have a multi-part or multilayer construction, and are intended in part to perform sealing and damping functions. The intermediate element described in German Patent Application No. DE 100 27 662 A1 has a base and carrier element in which a sealing means is set that is clamped by a nozzle element of the fuel injection valve. German Patent Application No. DE 100 38 763 A1 describes, a multilayer compensating element that is made up of two rigid rings and an elastic intermediate ring sandwiched between them. This compensating element enables both a tilting of the fuel injection valve relative to the axis of the receiving bore over a relatively large angular range and a radial shifting of the fuel injection valve out of the mid-axis of the receiving bore.
European Patent No. EP 1 223 337 A1 also describes a multilayer intermediate element, this intermediate element being made up of a plurality of washers made of a damping material. The damping material, made of metal, rubber, or PTFE, is selected and designed so as to enable a damping of the vibrations and noise produced by the operation of the fuel injection valve. However, for this purpose the intermediate element must have four to six layers in order to achieve the desired damping effect.
Damping elements in disk form for a fuel injector, in particular an injector for injecting diesel fuel in a common-rail system, are also described in German Patent Application No. DE 10 2005 057 313 A1. The damping disks are to be installed between the injection valve and the wall of the receiving bore in the cylinder head in such a way that even given high pressure forces a damping of structure-borne sound is enabled, so that noise emissions are reduced. An annular surface of the annular damping element abuts the support surface of the cylinder head, and a circumferential bulge of the damping element abuts the conical support surface of the injector. However, this overall system has the disadvantage that the support points of the damping element on the cylinder head and on the injector, regarded in the radial direction, are situated fairly close to one another, and the damping element is realized with a fairly high degree of rigidity due to its installation situation. This has the result that with the use of this system noise emissions are still present that can be heard clearly.
In addition, in order to reduce noise emissions, U.S. Pat. No. 6,009,856 A describes that the fuel injection valve be surrounded by a sleeve and that the resulting intermediate space be filled with an elastic sound-damping compound. However, this type of noise damping is complicated, difficult to install, and expensive.